Study On Hydration Treatment Of Ethylene Glycol Gas Field

With the growing size of oil and gas exploration, oil and gas wastewater showed a rapid growth. In the process of natural gas exploration, due to the changes in temperature and pressure, it is easy to generate gas hydrate, which is a snow-like compound, easy to plug the wellbore, pipeline and the layer. It can seriously affect the production and transportations. Glycol, as a hydrate inhibitor, can avoid the formation of gas hydrate effectively. As the great demand of glycol, wastewater contained large amount of glycol. Now the gas wastewater from a desert oilfield in Xinjiang contains large amounts of glycol, resulting in high COD. Due to the unique geological conditions, reinjection is impracticable, only post-processing efflux is feasible. Aiming at this situation, the thesis studied the anaerobic-aerobic biochemical process route by using lab-made biochemical reactor. Based on the monitoring data of each reactor during start-up phase and the stable phase, variation of COD in wastewater under different process parameters was analyzed, from which established the optimal parameters for each reactor. Aerobic kinetics of glycol gas wastewater was also introduced in detail. With the premise that the two reactors operate stable, combine the two reactors as a whole. The situation of pollutants removal of the overall process was studied. The main results of this experiment are summarized as follows:(1) During the anaerobic reactor start-up phase, the influent load increased from 1～3kgCOD/(m3·d) to about 13kgCOD/(m3·d). The final volume load maintained stability in 11.5 to 12.2kgCOD/(m3·d) after three months of acclimation, COD removal rate basically stable at 88% to 93%, gas production stabilized at about 11.8L, effluent COD maintained in 500 to 1500mg/L, and 24h was determined as the optimum hydraulic retention time. The reactor COD removal efficiency is higher when the influent C:N:P is 300:5:1.(2) When the influent COD of aerobic reactor within the range from 500 to 1500mg/L, the optimum hydraulic retention time should be 10h, the temperature should be controlled at 15 to 20℃, the effluent COD can reach below the level of 100mg/L, the aerobic reactor has good load resistance capacity, the maximum load of aerobic reactor can reach within range from 0.9 to 1.1kgCOD/(m3·d).(3) The study of the overall process shows that COD, as well as content of ammonia and oil can achieve A standard in" Integrated wastewater discharge Standard " (GB8978-1996). SS also consistent with the requirements of the secondary emission standards, which meet the requirement of landscape water in desert area.